The filament of an electric bulb is made of

Carbon
Aluminium
Tungsten
Nickel

The correct answer is C. Tungsten.

Tungsten is a very strong metal that can withstand high temperatures. It is also a good conductor of electricity. These properties make it ideal for use in the filament of an electric bulb.

Carbon is a good conductor of electricity, but it is not strong enough to withstand the high temperatures inside an electric bulb. Aluminium is a good conductor of electricity and is strong enough to withstand high temperatures, but it is not as good as tungsten at conducting electricity. Nickel is a good conductor of electricity and is strong enough to withstand high temperatures, but it is not as good as tungsten at conducting electricity or as resistant to oxidation.

Tungsten is the most common material used in the filament of an electric bulb. It is also used in other applications where high temperatures are required, such as in light bulbs, X-ray tubes, and welding equipment.